Hello Atsushi, On Thu, 23 Oct 2014 06:56:47 +0000 Atsushi Kumagai <kumagai-atsushi at mxc.nes.nec.co.jp> wrote: > >On Tue, 14 Oct 2014 07:19:13 +0000 > >Atsushi Kumagai <kumagai-atsushi at mxc.nes.nec.co.jp> wrote: [snip] > I noticed that is_vmalloc_addr_x86_64() can't be used as is_phys_addr() > due to the "kaslr issue". I fixed it in the common path as below, but > --mem-usage still has the same issue since initial() will be invoked > after get_kcore_dump_loads(). > > http://lists.infradead.org/pipermail/kexec/2014-October/012743.html > > I know it's so late, but I began to think the current implementation > that invokes vaddr_to_paddr_XXX() before initial() is bad: > > show_mem_usage() > + get_kcore_dump_loads() > + process_dump_load() > + vaddr_to_paddr_XXX() > + initial() > ... > vaddr_to_paddr_XXX() does VtoP translation *properly*, so it needs > several symbols. This design is OK since it's a general method. So the current implementation that uses vaddr_to_paddr_xxx() for --mem-usage *before* initial() is broken? Or does it currently works only by chance? > OTOH, we need a kludge which can be used under any situations and > should use it for --mem-usage: > > VtoP_kludge_s390x(unsigned long vaddr) > { > /* s390 has 1:1 VtoP mapping that starts with zero. */ > return vaddr; > } > > also x86_64's can be implemented like below: > > VtoP_kludge_x86_64(unsigned long vaddr) > { > /* if the address is direct mapped, it's easy to translate. */ > unsigned long paddr = vaddr - PAGE_OFFSET; > return paddr; > } What about using the kernel name __pa(vaddr)? [snip] > >--- a/elf_info.c > >+++ b/elf_info.c > >@@ -854,7 +854,7 @@ int get_kcore_dump_loads(void) > > > > for (i = 0; i < num_pt_loads; ++i) { > > struct pt_load_segment *p = &pt_loads[i]; > >- if (is_vmalloc_addr(p->virt_start)) > >+ if (!is_phys_addr(p->virt_start)) > > This part implicitly does VtoP translation. > Actually it works for s390x but it's not suitable as a general code, > so we should use VtoP_kludge(should be better name!) too. > Then we can use is_iomem_phys_addr() also for other architecture. So how exactly should the code look like for non s390x architectures? Michael
